The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.
Transflective LCDs may be used in cell phones, electronic books, and computers in part because reading transflective LCDs typically is possible in strong ambient lighting. A transflective LCD comprises an array of pixels or sub-pixels each having a reflective part and a transmissive part and may operate in different modes.
Under some approaches, a normally black transflective LCD may need a driving voltage higher than 5 Vrms (“root mean square”) to obtain high transmittance and reflectance, thereby requiring relatively high power consumption.
Under some other approaches, a normally white (NW) transflective LCD utilizing the electrically controlled birefringence effect may require a pair of wide-band quarter-wave films to realize the NW mode, which typically consists a half wave plate and a quarter-wave plate in the transmissive part, and a wide-band quarter-wave film in the reflective part. A costly nematic-hybrid retarder or similar compensation retarder is often required to achieve the dark state with voltage-on for a thin film transistor (TFT) driver under these approaches. The driving voltage is typically higher than 3.0 Vrms, thereby requiring relatively high power consumption.
In addition, the NW transflective LCD may comprise a liquid crystal layer working as a quarter-wave plate, which requires relatively tight and accurate cell gap control in manufacturing processes, thereby reducing the yield and increasing the cost in the manufacturing processes.
The drawings are not rendered to scale.